"Classic gearbox oils no longer fulfill the highest requirements"

Oil expert Oliver Kuhn of LIQUI MOLY explains the features of modern gearbox oils

26. September 2017

Oliver Kuhn, deputy head of the LIQUI MOLY oil laboratory

September 2017 – With the TOP TEC MTF 5200 75W-80 and TOP TEC MTF 5100 75W gearbox oils two new special lubricants by LIQUI MOLY are launching on the market at once. Oliver Kuhn, deputy head of the LIQUI MOLY oil laboratory, explains the properties and areas of use of the two new products.

What do the new LIQUI MOLY gearbox oils do that's so special or what is characterizing for you?Oliver Kuhn: Similarly to motor oils, the gearbox oil area has permanently moved on from the early, rather simple and clearly separated transmission and axle gearbox oils. It used to be that the transmission gearbox oils mentioned above had only mild additives in order to control their behavior towards the synchronizer rings. By contrast, the axle oils had significantly higher additives, as there are usually higher pressures in these motors. This separation often no longer exists today; everything is fitted together in the gearbox.Today the products have to combine several properties with one another. The classic oils can often no longer be used. New materials make it necessary to back new additive combinations. Add to this, much as in the motor oil area, the trend towards ever thinner oils. It used to be that oils such as SAE 85W-90 or 80W-90 were usual, going up to SAE 75W-90 and today it is 75W or 75W-80. The low viscosity is used to minimize wear losses and therefore to save fuel. And that is precisely what the two new gearbox oils do, which are predominantly differentiated by their area of use.

What areas of use are there for the new gearbox oils?Oliver Kuhn: Due to the ever changing oil requirements of the car manufacturers these gearbox oils open up new areas of use. Wear characteristic, material compatibility, pressure absorption or even viscosity are edging ever further into focus. The new gearbox oils also make it possible to cover the requirements of modern car transmission gearboxes, which classic transmission gearbox oils are no longer capable of doing.If you take into account the market for Japanese and American cars in this area, it becomes clear that many manufacturers still back API GL 4 and API GL 5 and therefore still allow older gearbox oils. The biggest differentiation here is in the European OEM area; outside of Europe this trend is still limited. Similarly to motor oils, it is also the case here that the API and ILSAC approvals differ significantly less and, in contrast to in Europe, the ACEA and the OEM are a lot more complex.